In deepwater drilling rigs, marine risers extending from a wellhead fixed on the ocean floor have been used to circulate drilling fluid or mud back to a structure or rig. The riser must be large enough in internal diameter to accommodate a drill string or well string that includes the largest bit and drill pipe that will be used in drilling a borehole. During the drilling process drilling fluid or mud fills the riser and wellbore.
It is contemplated that the term drill string or well string as used herein includes a completion string and/or displacement string. It is believed that rotating and/or reciprocating the drill string or well string (e.g., completion string) during the displacement and/or frac processes helps such processes.
There is a need to allow rotation and/or reciprocating during displacement and/or frac jobs while the annular blow out preventor is closed on the drill, completion, and/or displacement string.